This invention relates generally to optical systems and, more particularly, to an improved optical focusing system for redirecting substantially all of the light rays being emitted from a light source along a single projecting axis to form a high intensity, spotlight-type beam.
To designers and builders of optical focusing systems, it is well known that in many instances it is advantageous to provide a strong, focused beam that can be directed to a relatively small area. Spotlights of all types are an excellent illustration of the usefulness of such beams. On the other hand, there are many circumstances in which a divergent beam of light is particularly desirable. For example, a strong divergent beam of light is often used for nighttime exterior illumination purposes.
The common flashlight is one example of the incorporation of an optical focusing system into an illuminating apparatus. The usual optical focusing system found in a flashlight includes a parabolic reflector which partially surrounds a light bulb. The light bulb is situated generally at the focus of the parabolic reflector so that light emitted from the light bulb is reflected by the parabolic reflector parallel to its principal axis.
Many attempts have been made to modify or vary the construction of ordinary optical focusing systems in an effort to find a more efficient and satisfactory design. For example, one such modification utilizes three reflecting surfaces to substantially surround a light bulb for the purpose of collimating most of the emitted beams of light through a relatively small aperture in one of the reflecting surfaces. In another modified optical focusing system a plurality of reflecting surfaces are associated with a lens to effect a uniform dispersion and diffusion of the light over a predetermined field without sustaining the light losses suffered in prior distributing devices. Also, attempts have been made to design systems for gathering substantially all the light rays from the light source into a projected light beam through the use of one or more reflector/lens combinations.
Such optical focusing systems and illumination devices are subject to several disadvantages and drawbacks, however. One such drawback is the fact that undue complication of the reflector/lens configuration decreases the commercial marketability of the system. Another drawback is that, in spite of various lens and reflector arrangements, an optical focusing system which controls the direction of projection of every available light ray and is capable of collimating substantially all of the available light being emitted from a light source has not been previously devised.
Accordingly, there has been a need for an improved optical focusing system which can collimate substantially all of the light emanating from a light source. The system must be simple to construct, inexpensive, and sufficiently utilitarian so that a device embodying the system could be manipulated to produce either a spotlight-type beam or a divergent beam. Additionally, the improved optical focusing system should be readily adaptable for use as part of a portable illumination device as well as a much larger permanent or semi-permanent lighting installation. The present invention fulfills these needs and provides other related advantages.